This could be a simple bruise
over your muscle or a hard hit on the bone may have caused a crack there. Also the pain may be severe without any fracture
but because the bone faced the impact.
First, this would generally take about two weeks, to get the pain subsided , in absence of a fracture. Second you must confirm it with an x-ray done. Third, apply pain relieving gels over the impact area and take general painkiller and anti-inflammatory medicines available at a medical store. fourth, You should give your foot more rest and use a 'crepe bandage' to keep it from any further undue movement .
The x-ray findings would tell about further manageent of your problem, which you should discuss with an orthopedic person.
Do well and report back!